A Novel Gd3+-Pb2+ Doped LiSrPO4 Phosphor for Phototherapy Lamp Applications

The phosphors LiSrPO4:Gd3+ and LiSrPO4:Gd3+, Pb2+ with different concentration of Gd3+ and Pb2+ were synthesized by combination of re-crystallization and modified solid state diffusion method. The synthesized phosphors were characterized using XRD, SEM and PL spectroscopies. The PL excitation spectra of LiSrPO4:Gd3+ phosphor exhibit peak at 275 nm due to the S-8(7/2) -> I-4(J) transition of Gd3+ ions and gave narrow UVB emission at 312 nm. The effect of Pb2+ ions on the PL properties of LiSrPO4:Gd3+ have also been investigated. Upon the addition of Pb2+ ions, the excitation of phosphors shows broad peak with maximum at 247 nm, overlapping the Hg 253.7 nm line. This addition of Pb2+ ions improved the emission intensity of narrow band UVB i.e. 312 nm under the excitation of 247 nm. The phosphor could be good candidate as phototherapy lamp phosphor material.